Centrifugal pulp-screen



G. F. SHEVLIN.

CENTRIFUGAL PULP SCREEN.

APPLICATION FILED FEB. 18, 1919.

1,331,587. Patented Feb. 24, 1920.

4 SHEETS-SHEET 1- ,FZQJ,

G. F. SHEVLIN.

CENTRIFUGAL PULP SCREEN.

APPLICATION FILED FEB. 18, 1919.

1 3 3 1 587 Patented Feb. 24, 1920.

4 SHEETS-SHEET 2.

G. F. SHEVLIN.

C E N T R I F U GAL P U L P SC R E E N APPLICATION FILED FEB. 18, 1919.

1,331,587, I Patented Feb. 24,1920.

4 SHEETS-SHEET 3- G. F. SHEVUN.

CEN-TRIFUGAL PULP SCREEN.

APPLICATION FILED FEB. 18, 1919.

1,331,587. Patented Feb. 24, 1920.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

GEORGE E. SHEVLIN, 0F GLENS FALLS, NEW YOB-g, ASSIGNOB '10 NORTHERN NEWYORK FOUNDRY & MACHINE CO. INC., OF GLENS FALLS, NEW YORK, A CORPORA-TION OF NEW YORK.

CENTBIFUGAL PULP-SCREEN.

Specification of Illectcn Patent- Patented Feb. 24, 1920.

Application filed February 13, 1919. Serial Ira-277,127.

To all whom it may concern:

Be it known that I, GEORGE F. SHEVLIN, a

.citizen of the United States, residing at reticulated plates etachablyconnected with each other and supported on the frame of the machine. Insuch machines provision is made for separately collecting the screenedstock, and the sliver, lumps, and other refuse and foreign matter, andthe casing is made in detachable sections to provide for access to thescreen plates when they require repairs or when it is necessary toreplace them.

According to my present invention, I sim plif the construction of themachine and so change the relation of the beater blades with each otherand to the discharge 0 nings in the cylinder as to increase their eciency in discharging the pulp from the cylinder and against the screensand in discharging-the slivers, lumps and other foreign matters from thelower portion of the cylinder into the trough provided to receive them.I also so mount and connect the screens that they may be more readilyseparated and removed from the machine when they require repairs or itis necessary to replace them. Other 3--2. of Fig. 1.

features of the invention will be hereinafter In the accompanyingdrawings Figure 1 shows a vertical sectionthrough a centrifugal pulpscreen embodfi riag my improvements on the line 1--1 of ig. 2.

Fig. 2 shows a transverse section on the line 22 of Fig. 1.

Fig. 3 shows a similar section on the line Fig. 4 is a side view of thecylinderor barrelcarrying the beater blades and the devices fordischarging refuse or foreign matter.

Fig. 5 is a pers i 've view of a portion of the beater-carryingcylinder.

Fig. 6 is an end view of oneof the screen sections.

Fig. 7 is a perspective view showing portions of two of the screensections.

Fig. 8 is a detail view In section, showing how .two adjacent screensections are, connected with each other.

Fig. 9 is a perspective view of a single screen section.

Fig. 10 is a perspective view further illustrating how the screensections are connected with each. other.

Fig. 11 is a sectional view of a modification, the section being similarto that shown in Fig. 2, but showing a slightly difierent arrangement ofthe beater blades.

Fig. 12 is a perspective view, showing partioularly'the devices fordischarging foreign matter into the receivin trough, and

this figure of the drawings a so shows therelation of such devices withthe cylinder and the beater blades carried thereby.

As my" improvements do not involve changes in all parts of the machine,I have shown only such portions thereof as are necessary to illustratemy invention. Unless otherwise specified the parts shown are of wellknown construction.

The paper stock is fed to the machine through an inlet A. The screenedstock is received b a trou h B and the sliver or unstrained stock, incuding all foreign matter, is received by a separate trough C. The shaftD is supported in suitable bearings and extends centrally through thebeatercarrying cylinder or barrel E. The cylinder 1s formed with anarrow horizontal upper flange f and a wider downwardly inclined bottomflange f which latter extends artway over the inner edge of the troug O.

The cylinder is closed at its lower end, as

dicated at f.

Within the cylinder are arranged a series of vertical radially'arranged,curved beater blades 9 and similar beater blades g are arranged on theoutside of the cylinder. Preferably the body of the cylinder, theflanges f,

f, bottom plate f and the blades 9, g are made in a single casting, theinner blade 9 being formed with a hub g which is secured to the shaft Dso that the cylinder and the bladesrevolve with the shaft. The upperends of the blades 9 are of the usual form,

as indicated in Fi 1, and said blades extend from the top of t ecylinder to the bottom thereof. Lateral o nings or slots h are formed inthe oylin er to permit the liquid cases.

pulp to pass from the interior of the cylinder to the outside thereofand thus enter the annular chamber in which the blades 9' 'operate.

It will be observed, by reference to Fig. 2, that the outer blades 9 arenot direct continuation of the inner blades 9 but are out of linetherewith.

It will also be observed, by reference to Fig. 2, that whereas theconvex sides of the blades 9 act upon the pulp within the cylinder theconcave sides of the blades g act on the pulp outside the cylinder. Theopenings h in the side of the cylinder E are in front of the outer endsof the blades 9 and just behind the inner ends of the blades g, eachopening being thus a considerable distance in advance of the first bladeof the, outer series which actson the pulp flowing out of said opening.This is an important improvement made by me, for the reason that thepulp is prevented from flowing too rapidly through the apparatus becauseInasmuch as it is thrown out through the openings h by action of theconvex blades 9, as well as by centrifugal force, it is not immediatelyacted upon by the outer concave heaters but a short time elapses beforethe heaters act upon the pulp flowing through said openings. The pulpflowing downwardly through the cylinder E tends to continue its downwardmovement by gravity, but also tends to flow laterally through theopenings h by centrifugal force and by the action of the beater blades 9which being convex assist in throwing the pulp through said openings.The pulp is detained in the spaces between the heater blades 9 beforepassing through the openings 71, and thus is not immediately thrown outby centrifugal force. Some of the pulp is immediately thrown out bycentrifugal force while other portions of the pulp descend and are then'thrown out by centrifugal force, thus the output of the machine isincreased and a larger surface of the screen is utilized. Furthermore,by employing outer beater blades of the kind shown, which present aconcave surface to the pulp passing out of the cylinder, the pulp whichenters the annular space traversed by the outer blades is prevented frompassing too quickly against the screen and thus is made to distributeitself over an extended surface thereof so that practically the entirevertical surface of the screen is utilized.

The heaters g operate in an annular chamber formed between the cylinderE and the cylindrical screen K which surrounds the outer edges of thebeaters but is arranged a short distance therefrom as is usual in suchThe particular construction of the screen will be hereinafter described,but the operation of the apparatus will now be clear. The pulp enteringat A passes down into the cylinder E, and the fine pulp passes outthrough the openings h and is thrown by the outer heaters 9 against thecylindrical screen. The stock which passes through the screen isreceived by the trough B and is conveyed away in the usual way. Suchstock as falls to the bottom of the machine outside the cylinder E andonto the inclined flange f passes therefrom into the trough C. Much ofthe stock and the lumps, chips and foreign matter does not pass throughthe openings 71. but drops to the bottom of the cylinder E. In order todischarge this stock and the refuse or foreign matter that may be mixedwith it and prevent it from clogging the machine, openings m of largearea are formed in the lower portion of the cylin-.

der above the flange f. Whatever material or substances reaches thebottom of the cylinder passes out through these openings and over theflange f into the trough C.

In order to properly direct the material passing through the openings mand to deliver it to the trough C, I provide hoods M which have upperclosed sides m and curved vertical front faces m Fig. 12 of the drawingsclearly illustrates the construction of these hoods and their relationwith other parts of the apparatus.

It will be observed that the openings m are quite extended so as topermit unstraine stock and foreign matter to freely pass out from thebottom of the cylinder. The material thus passing through the openings menters the hoods M and is delivered from the rear portions of the hoods.The front portion the apparatus is so clearly shown in the drawings thata detailed description of this feature of the invention is deemedunnecessary. The convex front sides of the hoods, as before stated, soact upon the material as to cause it to pass into the trough C withoutbeing thrown against the screen plates. This is an advantage inasmuch'asparts of machines, pieces of wood and other heavy material are oftenmixed with the pulp and it is desirable that suchmaterial should bedelivered to the trough C without beingthrown against the screen plates.

The exterior casing N is madein sections as heretofore. No attempt hasbeen made to illustrate the details of construction of the "casing andit need not be described further than to say that the sections areremovable in order that access may be had to the screen plates orsections which are also removable in order that they may be repaired orreplaced at proper times. I have,

owever, provided means for so supporting and joining the screen platesthat they may be very quickly connected and disconnected and removedwhen the casing is opened and in like manner replaced. My improvementsin this connection are most clearly illustrated in Figs. 6-10,inclusive, of the drawings. Each screen section is of the general formshown in Fig. 9. The reticulated part 0 may be made of perforated platesor other suitable reticulated material and the perforated portion of thescreen is surrounded by a suitable frame 0'. The vertical sides of theframes are formed with key-hole slots 0 so constructed and arranged thatthe larger portion of each opening may easily pass over the head of abolt. To connect the screen sections with each other, I employ bolts Q,carrying nuts 9. The bolts pass through the vertical side pieces of twoadjacent screens, as illustrated in the drawings, and when the nuts arescrewed home the screen sections are rigidly connected with each other,and form a cylindrical screen which rests on the vertical flange R whichseparates the troughs B and C. The screen is so supported that it may beturned about a vertical axis, so as to bring each section opposite anopening in the casing made by removing one of its sections and then eachsection or any section may be removed through this opening. In this way,it will be observed, it is not necessary to remove all sections ofthecasing when it is desired to romove the screen plates, and it will alsobe observed that it is not necessary to dismantle other parts of themachine when desiring to remove a screen section. When the screensections are being assembled they are brought together in the mannerindicated in Fig. 8 and bolts are passed through thelarger portions ofthe slots or openings 0 then the bolts are dropped into the narrowerportions of the slots and the nuts are screwed home. When it is desiredto remove the screen sections the nuts are loosened, the bolts are movedvertically into the larger portions of the slots and are then drawnlaterally through said slots. In this way the screen sections aredisconnected and any section may be removed without disturbing theothers, or they may all be re-' moved if desired after the nuts havebeen lar to the section shown in Fig. 2, but it will be observed thatthe arran ement of the beater blades is slightly di erent. In this casethe inner beater blades 8 are made concave on their front faces andtheir outer ends are in front of the adjacent openings in the cylinder.The, outer blades 8' are similar to those shown in Fig. 2, and therelation of these blades to the openings h is the same.

The construction shown in Fig. 11 works well but that shown in Fig. 2 ispreferred. In both cases, it will be observed, the outer or exteriorblades are concave and tend to detain the pulp and in each casethe innerend of each outer blade is in front of the adjacent opening in thecylinder. In both cases the blades for propelling the pulp through theslotted cylinder are used in connection with the devices particularlyshown in Fig. 12 for expelling lumps, slivers and other larger andheavier material from the lower part of the cylinder.

I claim as my invention:

1. A centrifugal pulp screen, comprising a cylindrical screen, means forseparately receiving the screened and unscreened stock, and a revolvingcylinder within the screen having lateral openings and provided withinterior blades having convex sides operating on the pulp within thecylinder and exterior blades having concave sides operating on the pulpoutside the cylinder.

2. A centrifugal pulp screen, comprising a cylindrical screen, means forseparately receiving the screened and unscreened stock, and a revolvingcylinder within the screen having lateral openings and provided withconvex interior blades o crating upon the pulp within the cylin er, andexterior blades, the inner ends of which are disposed 3. A centrifugalpulp screen, comprising a cylindrical screen, means for separatelyreceiving the screened and unscreened stock, and a revolving cylinderwithin the screen having lateral openings and provided with interiorblades operating upon the pulp within the cylinder, and exterior blades,the inner ends of which are disposed in advance of the adjacent openingson the cylinder and in advance of the outer ends ofthe next adjacentinterior blades.

4. A centrifugal pulp screen, comprising a cylindrical screen, means forseparately receiving the screened and unscreened stock, and a revolvingcylinder within the screen having lateral openings and provided withinterior blades, the outer end of each. of which is disposed close toand on one side of an opening in the cylinder, and exterior blades, theinner end of each of which is disposed close to and on the opposite sideof each of said openings in advance of the outer end of an interiorblade.

5. A centrifugal pulp screen, comprising a cylindrical screen, means forseparately receiving the screened and unscreened stock,

and a revolving beater-carrying cylinder having side openings throughwhich the pulp passes to the screen, a closed lower wall or bottom plateover which the pulp passes laterally, and enlarged side openings throughwhich the pulp flows over said bottom plate from the cylinder, and hoodspartially surrounding said openings and through which the stock passeslaterally between the hoods.

6. A centrifugal pulp screen, comprising a cylinder screen, means forseparately receiving the screened and unscreened stock, a revolvingbeater-carrying cylinder having side openings through which the pulppasses to the screen,'a closed lower wall or bottom plate and havingenlarged side openings through which the pulp passes laterally from saidbottom plate, a downwardly inclined flange extending from said bottomplate to the receiver for the unstrained stock, and hoods above saidinclined flange having convex front faces acting en the material passingout of said side openings over said flange.

7. A centrifugal pulp screen, comprising a revolving beater-carryingcylinder having lateral openings through which the pulp is delivered,and a surrounding cylindrical screen mounted to turn about a verticalaxis and made in sections detachably connected with each other.

8. A centrifugal pulp screen, comprising a revolving beater-carryingcylinder having lateral openings through which the pulp is delivered, asurrounding cylindrical screen rotatable about a vertical axis and madein sections detachably connected with each other, and a casingsurrounding said screen having one or more removable sections.

10. A centrifugal pulp screen, comprising.

a revolving beater-carrying cylinder having lateral openings throughwhich the pulp passes, and a surrounding screen made in detachablesections each of said sections being formed with key-hole slots in itsvertical side portions and bolts carrying tightening nuts arrangedinsaid key-hole slots, said bolts being removable through the widerportions of said slots but being held from removal when in the narrowerportions of said slots.

11; A centrifugal pulp screen, comprising a cylindrical screen, meansfor separately receiving the screened and unscreened stock, and arevolving cylinder within the screen having lateral openings andprovided with interior blades operating upon the pulp in the cylinder toexpel it through said openings, and exterior concave blades havingconcave sides operating on the pulp outside the cylinder to deliver itto the screen, said cylindrical screen having side openings in its lowerportion provided with hoods having convex front sides operating upon thepulp delivered through said side openings to rotate it and to deliver itto the receptacle for unstrained stock.

In testimony whereof I have hereunto subscribed my name.

GEO. F. SHEVLIN.

